Short answer, because you asked a specific question and deserve a specific answer: 250 mg works. It’s a real dose from real trials, and it beat placebo. But 500 mg has the bigger and more consistent pile of evidence behind it, and if your problem is sustained attention rather than a general fog, that’s the number I’d aim for.
Dose used in the researchDose in the product
Trial doses as cited in this article
What I’m not going to tell you is that 250 mg is a waste of money. You’ll read that a lot. It’s wrong, and I can show you why.
Here’s what’s on this page:
- The three human trials, and which dose each one used
- Why the famous “13.6% brain energy” number is not in the paper it’s credited to
- The 2026 review that went the other way, which nobody quotes
- What’s actually in the bottle you probably own
- What I take, and why I stopped worrying about it
What the trials actually used
Three human trials matter here. I’ve read all 3 and I’ll give you the doses first, because that’s the whole question.
The first one took 75 healthy adolescent males and gave them either 250 mg or 500 mg. Both groups did better on attention and psychomotor speed than placebo. The interesting bit: when the researchers adjusted for body weight, the higher dose predicted better accuracy. So more was better, but less still worked.
The second took 60 women aged 40 to 60 and ran for 28 days at 250 mg or 500 mg. The 250 mg group made fewer errors of both kinds on a sustained attention test. The 500 mg group’s improvement was sharper on one measure. Again: both doses did something.
The third is the biggest and it’s the one that makes me lean high. 148 adults aged 35 to 75, all of them already struggling with sustained attention, 500 mg a day for 12 weeks. Their reaction times got faster on the attention tasks. That study didn’t test 250 mg at all, which is exactly why the evidence at 500 mg looks deeper. It isn’t that 250 failed. It’s that nobody asked it the same question.
That distinction matters more than most people writing about this seem to notice. “Less evidence” and “evidence of less” are not the same sentence.
READ: My top 3 best nootropic supplements, with every dose checked
The 13.6% figure is not real
You’ve seen it. “Citicoline increases brain energy by up to 13.6%.” It’s on product pages, it’s in blog posts, and it was on my own site for years. I put it there.
So I went and read the paper it gets credited to. It’s a 2008 brain-scan study, and here is what it actually measured, in people taking 500 mg or 2,000 mg for 6 weeks:
- Phosphocreatine up about 7%
- ATP up about 14%
- The ratio of phosphocreatine to inorganic phosphate up about 32%
No 13.6% anywhere. Somebody, at some point, averaged something or misread a table, and the number got copied from site to site until it looked like a fact. I copied it too, which is the annoying part.
The real numbers are better than the fake one, honestly. A 32% shift in that ratio is a big change in how a brain handles fuel. But notice the doses in that study: 500 mg and 2,000 mg. Nobody scanned anyone’s head at 250 mg. So if the brain-energy argument is what sold you, the dose that argument was built on is 500 mg and up.
The 2026 review nobody quotes
A review site where every ingredient wins is a catalogue, so here’s the one that went the other way.
In 2026 a systematic review pulled together 11 controlled trials of citicoline and phosphatidylserine in people with mental-health conditions. ADHD, mood disorders, substance use, schizophrenia. Its conclusion was blunt: the evidence doesn’t support either one as a cognitive enhancer in those groups, and the studies had real problems with how they were run.
Now, that’s a narrower question than yours. If you’re a healthy adult who wants to focus better on a Tuesday afternoon, the trials that speak to you are the healthy-adult ones I listed above, and those are still positive. But I’m not going to quote the flattering studies and bury this one. That’s how you end up trusting a website that’s only ever selling.
What’s in the bottle you own
Go get it. I’ll wait.
Most stacks carry 250 mg, usually as Cognizin, which is the branded form nearly every trial used. Mind Lab Pro has 250 mg in a 2-capsule serving. Performance Lab Mind has 250 mg too.
Here’s the thing I want you to take away, and it’s why I keep banging on about reading the label. When I audited a popular stack against the studies used for each of its ingredients, most of them came up short. Bacopa at half the trial dose. Lion’s mane at a quarter. Rhodiola at under a third of the lowest dose that’s ever worked in a trial. Citicoline was one of only 2 that matched.
So citicoline is the ingredient the industry gets right. If you’ve been told your 250 mg is fairy dust, whoever told you that didn’t check.
READ: Nootropic doses vs. what the studies actually used
Standalone versus the stack
If you want 500 mg, you have 2 options and they cost very different amounts.
Option one is to take 2 servings of your stack. Don’t. You’d be doubling 10 other ingredients to fix one, and some of them you don’t want doubled.
Option two is to buy plain citicoline and take it alongside. Standalone capsules run cheap compared to a branded stack, and the cost per serving is a fraction of what you’re paying inside a formula. That’s what I do on the days I actually need it.
What I do
I take 250 mg most days because it comes inside the stack I already take, and I add a standalone 250 mg on days I know will be long. That puts me at 500 mg when it matters and 250 mg when it doesn’t.
Do I feel it? Sort of. It’s not caffeine. Nothing switches on. What my notes say, across a lot of weeks, is that the afternoon slump is shallower. That’s a boring result and it’s the honest one. I’ve had things on this site do nothing at all and I’ve said so, so you can take this as the small real effect it is.
Give it 4 weeks before you judge it, and hold your coffee and your sleep steady while you do. Otherwise you’re measuring your week, not the capsule.
Conclusion
250 mg is a studied, effective dose and the industry actually doses this one properly. 500 mg has more evidence behind it, especially for sustained attention, and it’s the dose the brain-energy scans used. Neither number is a con.
If you’re generally foggy, start at 250 mg and stop reading product pages. If your specific complaint is that you can’t hold attention on one task for an hour, go to 500 mg. And if anyone quotes you 13.6%, you now know something they don’t.
I’m not a doctor, and I say that on every page like this. If you take medication, especially anything for blood pressure or a stimulant for ADHD, ask a pharmacist before you add this. It’s a free conversation.
Questions in the comments and I’ll answer them. That would be it folks!
READ: My top 3 best nootropic supplements, with every dose checked
